Actually populate ForgeConstants

proxy/src/main/java/com/velocitypowered/proxy/connection/backend/BackendPlaySessionHandler.java

@@ -6,7 +6,7 @@ import com.velocitypowered.api.proxy.messages.ChannelIdentifier;
 import com.velocitypowered.proxy.VelocityServer;
 import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
 import com.velocitypowered.proxy.connection.client.ClientPlaySessionHandler;
-import com.velocitypowered.proxy.connection.forge.ForgeUtil;
+import com.velocitypowered.proxy.connection.forge.ForgeConstants;
 import com.velocitypowered.proxy.connection.util.ConnectionMessages;
 import com.velocitypowered.proxy.protocol.MinecraftPacket;
 import com.velocitypowered.proxy.protocol.ProtocolConstants;
@@ -84,7 +84,7 @@ public class BackendPlaySessionHandler implements MinecraftSessionHandler {
             return true;
         }
 
-        if (!serverConn.hasCompletedJoin() && packet.getChannel().equals(ForgeUtil.FORGE_LEGACY_HANDSHAKE_CHANNEL)) {
+        if (!serverConn.hasCompletedJoin() && packet.getChannel().equals(ForgeConstants.FORGE_LEGACY_HANDSHAKE_CHANNEL)) {
             if (!serverConn.isLegacyForge()) {
                 serverConn.setLegacyForge(true);
 
@@ -173,7 +173,7 @@ public class BackendPlaySessionHandler implements MinecraftSessionHandler {
         boolean isMCOrFMLMessage;
         if (serverConn.getConnection().getProtocolVersion() <= ProtocolConstants.MINECRAFT_1_12_2) {
             String channel = message.getChannel();
-            isMCOrFMLMessage = channel.startsWith("MC|") || channel.startsWith(ForgeUtil.FORGE_LEGACY_HANDSHAKE_CHANNEL);
+            isMCOrFMLMessage = channel.startsWith("MC|") || channel.startsWith(ForgeConstants.FORGE_LEGACY_HANDSHAKE_CHANNEL);
         } else {
             isMCOrFMLMessage = message.getChannel().startsWith("minecraft:");
         }

proxy/src/main/java/com/velocitypowered/proxy/connection/client/ClientPlaySessionHandler.java

@@ -7,6 +7,7 @@ import com.velocitypowered.api.util.ModInfo;
 import com.velocitypowered.proxy.VelocityServer;
 import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
 import com.velocitypowered.proxy.connection.backend.VelocityServerConnection;
+import com.velocitypowered.proxy.connection.forge.ForgeConstants;
 import com.velocitypowered.proxy.connection.forge.ForgeUtil;
 import com.velocitypowered.proxy.protocol.MinecraftPacket;
 import com.velocitypowered.proxy.protocol.ProtocolConstants;
@@ -144,7 +145,7 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
         } else if (PluginMessageUtil.isMCBrand(packet)) {
             player.getConnectedServer().getConnection().write(PluginMessageUtil.rewriteMCBrand(packet));
         } else if (player.getConnectedServer().isLegacyForge() && !player.getConnectedServer().hasCompletedJoin()) {
-            if (packet.getChannel().equals(ForgeUtil.FORGE_LEGACY_HANDSHAKE_CHANNEL)) {
+            if (packet.getChannel().equals(ForgeConstants.FORGE_LEGACY_HANDSHAKE_CHANNEL)) {
                 if (!player.getModInfo().isPresent()) {
                     ForgeUtil.readModList(packet).ifPresent(mods -> player.setModInfo(new ModInfo("FML", mods)));
                 }

proxy/src/main/java/com/velocitypowered/proxy/connection/client/ConnectedPlayer.java

@@ -26,7 +26,7 @@ import com.velocitypowered.proxy.VelocityServer;
 import com.velocitypowered.proxy.connection.MinecraftConnection;
 import com.velocitypowered.proxy.connection.MinecraftConnectionAssociation;
 import com.velocitypowered.proxy.connection.backend.VelocityServerConnection;
-import com.velocitypowered.proxy.connection.forge.ForgeUtil;
+import com.velocitypowered.proxy.connection.forge.ForgeConstants;
 import com.velocitypowered.proxy.connection.util.ConnectionMessages;
 import com.velocitypowered.proxy.connection.util.ConnectionRequestResults;
 import com.velocitypowered.proxy.protocol.ProtocolConstants;
@@ -400,8 +400,8 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player {
     public void sendLegacyForgeHandshakeResetPacket() {
         if (connection.canSendLegacyFMLResetPacket()) {
             PluginMessage resetPacket = new PluginMessage();
-            resetPacket.setChannel(ForgeUtil.FORGE_LEGACY_HANDSHAKE_CHANNEL);
+            resetPacket.setChannel(ForgeConstants.FORGE_LEGACY_HANDSHAKE_CHANNEL);
-            resetPacket.setData(ForgeUtil.FORGE_LEGACY_HANDSHAKE_RESET_DATA);
+            resetPacket.setData(ForgeConstants.FORGE_LEGACY_HANDSHAKE_RESET_DATA);
             connection.write(resetPacket);
             connection.setCanSendLegacyFMLResetPacket(false);
         }

proxy/src/main/java/com/velocitypowered/proxy/connection/forge/ForgeConstants.java

@@ -1,4 +1,12 @@
 package com.velocitypowered.proxy.connection.forge;
 
 public class ForgeConstants {
+    public static final String FORGE_LEGACY_HANDSHAKE_CHANNEL = "FML|HS";
+    public static final String FORGE_LEGACY_CHANNEL = "FML";
+    public static final String FORGE_MULTIPART_LEGACY_CHANNEL = "FML|MP";
+    public static final byte[] FORGE_LEGACY_HANDSHAKE_RESET_DATA = new byte[] { -2, 0 };
+
+    private ForgeConstants() {
+        throw new AssertionError();
+    }
 }

proxy/src/main/java/com/velocitypowered/proxy/connection/forge/ForgeUtil.java

@@ -12,10 +12,6 @@ import java.util.List;
 import java.util.Optional;
 
 public class ForgeUtil {
-    public static final String FORGE_LEGACY_HANDSHAKE_CHANNEL = "FML|HS";
-    public static final String FORGE_LEGACY_CHANNEL = "FML";
-    public static final String FORGE_MULTIPART_LEGACY_CHANNEL = "FML|MP";
-    public static final byte[] FORGE_LEGACY_HANDSHAKE_RESET_DATA = new byte[] { -2, 0 };
 
     private ForgeUtil() {
         throw new AssertionError();
@@ -23,7 +19,7 @@ public class ForgeUtil {
 
     public static Optional<List<ModInfo.Mod>> readModList(PluginMessage message) {
         Preconditions.checkNotNull(message, "message");
-        Preconditions.checkArgument(message.getChannel().equals(FORGE_LEGACY_HANDSHAKE_CHANNEL),
+        Preconditions.checkArgument(message.getChannel().equals(ForgeConstants.FORGE_LEGACY_HANDSHAKE_CHANNEL),
                 "message is not a FML HS plugin message");
 
         ByteBuf byteBuf = Unpooled.wrappedBuffer(message.getData());